Infectious Diseases Flashcards
Cellulitis
Most common causes
Beta-haemolytic strep (Strep pyogenes) and Staph aureus are most common causes
Cellulitis
Management
If clinically well - Fluclox PO 7-10 days
o If acutely unwell - Vanc IV for MRSA cover
Necrotising fasciitis
Causes
Type I - polymicrobial – anaerobe (Bacteroides) + facultative organism (non-group A strep, ie not pyogenes)
Type II - monomicrobial – Strep pyogenes
Pityriasis versicolor
Investigations
Management
Investigations:
- KOH preparation of affected skin - short hyphae and spores
Management:
- Topical antifungal is first-line, for 2 weeks
- Oral antifungal for extensive/treatment-resistant lesions for 2 weeks (Oral antifungals cannot be given in pregnancy)
Dermatophytosis
Investigations
Management
Investigations:
- Fungal nail infection – must be confirmed with KOH and culture or PAS staining from a clipping
- KOH microscopy if diagnosis unclear
Management
- Topical antifungal (Tinea capitis, corporis, cruris, pedis)
- Systemic antifungal (Nail, capitis)
Scabies
Management
Permethrin topical – apply for 8-14 hours, may repeat after 10-14 days if needed
Ivermectin is an oral alternative, may be preferred if large numbers of patients to treat (Avoid in <2 months and pregnant)
Chlamydia
First-line investigation
Management
First-line investigation:
- NAAT
Management:
- Azithromycin 1g PO single dose
- Or doxycycline 100mg PO BD for 7 days
• Not suitable during pregnancy
Gonorrhoea
Management
Dual-antibiotic therapy to also cover chlamydia:
• Ceftriaxone 250mg IM
• Azithromycin 1g PO single dose
Syphilis
Investigations
Management
Investigations:
- Dark-field microscopy
- Syphilis serology
- Non-treponemal test - VDRL test
Management:
- Benzylpenicillin IM
HIV
Investigations
- ELISA and p24 antigen – reduces window period from 3 months to 10 days
- Rapid test – useful in developing world
- CD4 count – normal is 800, >500 is asymptomatic, <350 is immune suppression, <200 is AIDS (PCP is most common infection)
HIV
Management
Vaccinations (pneumococcal, meningococcal, flu, hep B, HPV, tetanus/diphtheria/pertussis)
ART regimen
- 2 NRTIs + a third agent (INSTI or NNRTI or boosted PI)
Genital warts
Management
- Topical podophyllotoxin therapies
- Cryotherapy
Malaria
Management
If uncomplicated disease:
• 1st line - chloroquine PO
• 2nd line if chloroquine-resistant - artemether/lumefantrine PO
If severe disease:
• IV artesunate or IV quinine
Typhoid Mary
Investigations
Management
Investigations (often non-specific):
- FBC – low/normal WBC, mild anaemia, low/normal platelets
- Blood cultures 80-100% sensitive
- Stool/urine cultures
Management:
- If returning from India (resistant to cipro) - ceftriaxone IV
- If returning from outside India - ciprofloxacin IV
Typhoid Mary
Complications
- Bowel perforation and GI bleed (Peyer’s patches)
- Extra-intestinal involvement (CNS, pulmonary, bone and joints, myocarditis)
